1. Field
The present invention relates to a portable radio device and a radio communication method and, more particularly, to a portable radio device, which is communicatable via Bluetooth (Bluetooth: registered trademark) between battery-powered speaker-microphones and which is movable with the speaker-microphone, and the radio communication method therefor.
2. Description of the Related Art
There are available portable radio devices, which are communicatable, via Bluetooth, between battery-powered speaker-microphones (or headsets) that are movable with their speaker-microphones. Among those portable radio devices, a portable radio device, for communicating with a partner station using a simplex (half duplex) scheme, transmits a transmitting voice of a user collected by a speaker-microphone, via Bluetooth communications, to the portable radio device and further wirelessly transmits the transmitting voice from the portable radio device to a partner station through a relay station. At this time, the partner station is in a receiving state. When, on the other hand, the partner station is in a transmission state, the portable radio device is switched to a receiving state. Then the transmitting voice wirelessly transmitted from the partner station is received by the portable radio device via the relay station, and the transmitting voice received is further transmitted to the speaker-microphone via Bluetooth communications. As a result, the transmitting voice is received and produced as voice sound by the speaker-microphone.
In a portable radio device with a speaker-microphone for business or commercial use among those equipped with the speaker-microphones using the simplex (half duplex) scheme, the user starts a call immediately after a push-to-talk (PTT) switch at the outset of a communication is operated. Thus, a transmission state starts upon activation of the PTT switch, and an attack time at which the modulation is actually feasible is defined accordingly. In the receiving, too, a received voice is suddenly outputted unlike a mobile phone where the received voice is outputted after a telephone calling operation has responded to an incoming call.
Accordingly, for such a portable radio device equipped with the speaker-microphone for business use, it is preferable that the voice communication is constantly enabled within a call possible zone (e.g., wireless service area or radio communication enabled area), and the headset profile (HSP) is used as the Bluetooth profile. As a result, the battery saving of the speaker-microphone is not carried out.
Also, in the portable radio device with the speaker-microphone for business use, the battery saving of the battery-powered speaker-microphone is not done although conventionally the transmission and the receiving in the radio communication do not need to be controlled in an area outside the call possible zone (an out-of-service area). In this case, the electric power of the battery-powered speaker-microphone is constantly consumed in the conventional portable radio device with the speaker-microphone for business use, thus causing a problem of reduced battery life.
In the light of this, conceivable for the purpose of reducing the power consumed by the speaker-microphone is a method where the power saving is carried out, except during a call, using the hands-free profile (HFP) of the Bluetooth profile.
Also conceivable for the purpose of reducing the power consumed by the speaker-microphone is employing a known method, as cited in Reference (1) of the following Related Art List, for reducing the power consumed by a mobile terminal device. A conventional method, cited in Reference (1) of the following Related Art List, for reducing the power consumed by a mobile terminal device, is as follows. That is, when the device is not in used for a predetermined duration of time with a function being turned on, it is determined that the function be turned off and, at that time, the position and the power use state or condition of the mobile terminal device are registered. Then, in the thus registered position, control is performed such that the mobile terminal device is in the registered power use state. As a result, the functions not in use are turned off and therefore the wasted power consumption is reduced. The position of the mobile terminal device is acquired by a known method using a global positioning system (GPS).